I have 100m 10mm multiplait, 5kg Bruce and 7.5kg of chain (heavier than anchor for Alderney ring, not fussed on length). Boat is 4.8m.
3x your depth is recommended, and more if rough and deep with big tide.
Just think, if you are in trouble you want to be able to hold a good depth. It might be the one thing to keep you off the rocks!
With that in mind, ensure you have something to hand should you want to upgrade you 'tripped' anchor to fixed in an emergency.
R